Power driven stapling machine



June 29, 1965 w. SCHAFROTH 3,191,841

POWER DRIVEN STAPLING MACHINE Filed May 15, 1963 4 Sheets-Sheet 1 June 29, 1965 w. SCHAFROTH 3,19 ,841

POWER DRIVEN STAPLING MACHINE Filed May 13, 1963 4 Sheets-Sheet 2 17V men r02:

June 29, 1965 w. SCHAFROTH POWEE DRIVEN S TAPLING MACHINE I 4 Sheets-Sheet 3 Filed May 13, 1963 WfE/VEK 561M590? 3) z a, a g a:

June 29, 1965 w. SCHAFROTH 3,

POWER DRIVEN STAPLING' MACHINE Filed May 13, 1963 4 Sheets-Sheet 4 United States Patent 3,191,841 PGWER DREVEN STAPLING MACHINE Werner Schafroth, R0. Box 247, Herrin, iii. Filed May 13, 1963, Ser. No. 279,834- 3 (Ilaims. (Cl. 227-130) This invention relates generally to a power driven stapling machine, and more particularly, to an air operated stapling machine of the retractable anvil type.

One of the principal objects of the present invention is to provide a simplified air piston construction and control for operating a stapling machine of lesser height. Another object is to provide a simplified arrangement and construction so that parts which normally have to be serviced can be adjusted or removed and replaced with a minimum of eifort. A further object is to provide for the penetration control of retractable anvils which can be made without making any adjustment on the automatic tripping device. Another object is to provide a magazine for staples which does not require a stop to keep the pusher from going beyond the position where it places the last staple in driving position. Another object is to provide a driving blade and pusher construction which is designed to prevent injury to the machine in the event that the driving blade is driven down onto the pusher.

Another object is to provide an air operated stapling machine in which the piston is moved in both directions by air pressure and in which the exhausted air is directed through the stapling mechanism to free said mechanism from foreign particles and deposit a coating of oil on the parts, since oiled air is used to actuate the machine. Another object is to provide a machine whose casing is lower in height than previous machines. Another object is to provide a cast aluminum frame in which no moving parts of the stapling machine come into contact with the aluminum. Another object is to provide an adjustable piston rod in the power cylinder.

These and other objects and advantages will become apparent hereinafter.

The present invention is embodied in an air operated stapling machine which comprises a novel air cylinder and piston construction, easily removable and replaceable air control means, a novel magazine with a pusher, there being no pusher stop means in said machine, said machine being so constructed that the operating air when exhausted is directed through the stapling mechanism.

The invention also consists in the parts and in the arrangements and combinations of parts hereinafter described and claimed. In the accompanying drawings which form part of this specification and wherein like numerals and symbols refer to like parts wherever they occur.

FIG. 1 is a top plan view of a stapling machine embodying the present invention,

FIG. 2 is a vertical cross-sectional view taken along the line 2-2 in FIG. 1 and showing the piston in its upper or driving position and the trigger in its upper position,

'FIG. 3 s a fragmentary view similar to that shown in FIG. 2, except that the piston is shown in its lower or driven position and the valve trip lever is moved right- Wardly,

FIG. 4 is a fragmentary view showing the trigger in its lower position,

FIG. 5 is a bottom view of the stapling machine,

FIG. 6 is a front elevational view thereof, showing the anvil adjusting means,

FIG. 7 is a fragmentary view with the back plate off showing the anvil actuating mechanism, with the anvil on the right shown in its retracted position and the anvil on the left in its clinching position, said view being split to illustrate the operation of the machine,

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FIG. 8 is a bottom view of the air cylinder casting itself,

FIG. 9 is a vertical cross-sectional View taken along the line 9-9 of FIG. 8, and

FIG. 10 is a vertical cross-sectional view taken along the line 1i3-lil of FIG. 8.

Referring now to the drawings in detail, it will be seen that the embodiment of the invention which has been illustrated comprises a stapling machine M having an air cylinder C, a handle H with an air reservoir 1 therein and with a trigger 2 thereon, a stapling mechanism 3, and a magazine 4 for feeding staples to said stapling mechanism 3. The handle H is connected to a source of compressed air suitable for stapling machines.

The air cylinder C comprises an upper casing 5 and a lower casing 6. The upper casing 5 has a piston 7 therein with sealing means 3, such as an O-ring, in its outer peripheral margin. A bolt 9 extends through the piston 7, said bolt 9 having a shoulder 16) for receiving a washer 11 With a spring 12 thereabove between said washer 11 and said piston 7. This provides for adjustment of the piston 7 on the bolt 9. Sealing means 13 are provided between the central opening 14 in the piston 7 and the bolt 9, which has a lock nut 15 above the piston 7.

The upper casing 5 has an upper chamber 1!, formed by a peripheral chamber 17, a central chamber 18, and four cross chambers 19. The members 19a between the cross chambers 19 act as upper stops for the piston 7 and contact said piston 7 inwardly of the outer edge thereof where the piston is strongest. The upper casing 5 is also provided with a vertical opening 26 between the air cylinder C and the handle H, which slidably receives a plunger 21. The plunger 21 has a plunger stem 22, a plunger spool 23 having two grooved flanges 24 and 25 thereon, a rubber washer 26 in each groove, a compression washer and nut 27 above the spool 23, a compres sion washer and nut 28 below the spool 23, a return spring stud 29, and a plunger return spring 30. A plunger stop 31 is mounted at the bottom of said opening 20 and slidably receives the plunger stem 22. The plunger re turn spring 30 normally biases the plunger 21 downwardly to maintain the plunger stem 22 in contact with a valve trip lever 32 which is adapted to move horizontally rearwardly. The vertical opening 20 in the upper casing 5 has an opening 33 therein between the flanges 24 and 25 leading to the reservoir 1 in the handle H. The opening 29 is also provided with an upper port 34 and a lower port 35, and with a top exhaust port 36 adjacent to the plunger return spring 3%) and a lower exhaust port 37.

The valve trip lever 32 has a sloping forward face 38 adapted to abut a plunger or rod 39 mounted in a screw 40 and guide 41 positioned in an opening 42 in the lower casing 6, said plunger 39 having a spring 43 therearound to normally bias said plunger 39 to its upper position shown in FIG. 2. The plunger 39 has a top portion 44 which extends above the screw 40. The screw 40 extends slightly above the inside bottom surface of the air cylinder C to allow air to enter beneath the piston 7 at the proper time.

The valve trip lever 32 is slidably mounted in the trigger housing 45 with a return spring 46 secured thereto for normally biasing said trip lever 32 in its leftward position shown in FIG. 2. The trigger 2 is pivotally mounted on a pin 47 and has a trigger spring 48 mounted thereto and to a fixed pin 49 for normally biasing the trigger 2 to its lower position against a trigger stop 50. Rollers 51 are mounted on the pin 47 and a rearward pin for the valve trip lever 32 to slide upon.

The lower casing 6 is provided wtih a lower chamber 52, and a horizontal port or passage 53 which extends from the lower exhaust port 37 through exhaust passage 64 to an opening 54 in the bottom surface 55 of the lower casing 6. The stapling mechanism 3 may be of any suitable construction such as that generally shown in the Schafroth Patents Nos. 2,897,502, 2,897,503 and 2,740,- 1l9, which are of the retractable anvil type. As shown in FIG. 5, the adjusting mechanism 56 may be the same or similar to that shown in the Schafroth Patent No. 2,897,- 502, which describes the adjustment mechanism and operation of the stapling mechanism. The retractable anvils are mounted on a pin 56a which can be adjusted vertically to control the depth of the anvil penetration.

The bolt 9 is secured to a staple driving blade 57 whose lower edge 58 at the rear portion 59 is beveled, preferably at an angle of about 45. The magazine 4 is suitably secured to the stapling mechanism 3 and is provided with a pusher 60 and a spring 61 for biasing the pusher 60 toward the stapling mechanism 3. The upper edge 62 of the forward portion of the pusher 60 is beveled, preferably at a 45 angle, so that if an operator actuates the machine M after the last staple has been driven, the beveled driving blade 57 simply hits against the beveled surface 62 of the pusher 60 thereby driving the pusher 60 rearwardly and allowing the driving blade 5'7 to continue to its downward position without causing any harm or damage to the machine.

In operation, with the piston 7 in its upper or driving position, and with staples in the magazine, and with the proper amount of air directed to the machine, which air in practice contains a small amount of oil, when the trigger 2 is lifted upwardly from its normal downward position, the plunger 21 is lifted and causes the spool 23 to move to its upper position, as shown in FIG. 2. This allows air to move from the reservoir 1 in the handle H through the opening 33 and between the flanges 24 and 25 in the spool 23 and then into the upper port 34 and inclined passage to the upper chamber 16 above the piston 7. This upper chamber 16 has increased volume because of the peripheral chamber 17, the central chamber 18 and the cross openings 19, thereby allowing a greater quantity of air on the upper side of the piston 7. The pressure in the upper chamber 16 normally moves the piston 7 slightly downwardly compressing the spring 12 thereby increasing the volume above the piston 7.

The air forces the piston 7 downwardly until the washer 11 contacts the lower casing 6 and the piston 7 contacts the top portion 44 of the plunger 39, which plunger 39 then moves down and causes the valve trip lever 32 to move to the right or rearwardly until the hole 63 in the trip lever 32 aligns itself with the plunger stem 22, thereby allowing the plunger stem to drop into the hole 63.

As the piston 7 moves down, the air beneath it is expelled through the lower port 35 and lower exhaust port 37 to the exhaust passage 64 and passage 53 and out through the opening 54. The rightward movement of the trip lever 32 allows the spring to move the spool 23 to its lower position, as shown in FIG. 3, thereby closing off lower exhaust port 37 and opening the upper chamber 16 to exhaust through the upper port 34 which is then above spool 23 so that the air can enter the exhaust port 36 which leads to a vertical exhaust passage 64, as does the lower exhaust port 37, which directs it downwardly to the horizontal passage 53 in the lower casing 6 which directs it downwardly through the stapling machine itself. Thereby blowing out any foreign particles that might have gone into the stapling mechanism.

At this point, the spool 23 is in its lower position, as shown in FIG. 3, and air is allowed to move from the reservoir 1 through the opening 33 and into the opening 20 and into the space below the upper flange 24 of the spool 23 and then into the lower port which leads to the lower chamber 52 directly into the air cylinder C beneath the piston 7, thereby moving the piston 7 upwardly to the position shown in FIG. 2. As the piston 7 moves upwardly from its lowermost position, it allows the plunger 39 to move upwardly. Thus, the valve trip lever 32 can move leftwardly under the force of the light return spring 46 just as soon as the trigger 2 is released and allowed to fall or be pivoted downwardly under force of the trigger spring 48 thereby releasing the plunger stem 22 from the hole 63. As the piston 7 moves up, it moves the stapling mechanism 3 and staple driving blade 57 with it, since they are all operatively connected together.

The plunger 21 mounted in the opening 20 is designed to have the flanges 24 and 25 with washers 26 therein. By turning the nut 28, compression is exerted on the washers to increase their diameter. This is important for adjustment when the machine is first assembled and tested, and is also important in the maintenance of the machine after it has been in service for some time. The user of the machine will be able to stop any leakage in this valve by simply tightening two members, the stud 29 and the nut 28, and will therefore not have to wait for replacement parts. The position and design of the plunger 21 allows the machine to be serviced with case.

It is evident that the penetration control for the anvils can be set for the deepest to the shallowest position without making any adjustment to the automatic tripping device. This is done simply by moving the adjusting mechanism 56.

The foregoing machine can operate up to 580 strokes per minute on a test block. The frame of the machine is aluminum to give long life, but hardened steel is used for the driving blade guide and to support the anvils. A wear plate is provided on the front side of the machine where the anvil holders and plunger slide. The pusher 60 is designed so that it can operate without a stop. The air cylinder C is designed so that the thin edge of the piston at the sealing means 8 does not come into contact with the end of the cylinder bore. The cast aluminum frame is designed so that no moving parts of the stapling machine come in contact with the aluminum. The entire design presents a compact machine which is lower in height, which is desirable. The exhaust of oiled air from the air cylinder, both above and below the piston 7, is directed through passages to a port or opening 54 about A inch from the bolt 9 so that said oiled air is forced or blown downwardly through the stapling mechanism thereby removing foreign particles and automatically oiling the moving parts. Thus, the entire mechanism is constantly lubricated and cleaned during operation. This is important since stapling machines tend to get full of carton fibre during operation. The air cylinder C is designed so that the piston is stopped or hit near the center where it is strongest, the members 19a between the cross chambers 19 acting as four stops to limit the upward movement of the piston 7. The piston rod or bolt 9 is adjustable because of the spring 12 and lock nut 15 arrangement at the top thereof.

This invention is intended to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A power driven stapling machine having a stapling mechanism therein, an air cylinder connected to said stapling mechanism, said air cylinder being operatively connected to a source of compressed air, a trigger pivotal ly mounted on said machine, a piston slidably mounted within said air cylinder, said piston having a rod operatively connected to said stapling mechanism, an air chamber above said piston, said air chamber having downwardly extending members therein adapted to contact and form an upper stop for said piston substantially inwardly of the peripheral edge thereof, said piston being re- I siliently mounted on said rod, valve means for directing compressed air above said piston and exhausting air from below said piston, said valve means mounted in said air cylinder casing in a separate opening removed from said air piston, lower stop means for said piston mounted in the bottom of said air cylinder and positioned to contact said piston inwardly of its peripheral edge, said lower stop means having a plunger therein adapted to contact a valve trip lever for moving said valve means to a position for allowing compressed air to enter beneath said piston and exhaust the air from above said piston.

2. An air operated stapling machine having a stapling mechanism therein, a magazine secured thereto for feeding staples thereto, an air cylinder connected to said stapling mechanism, said air cylinder having a handle with an air reservoir therein, a trigger pivotally mounted on said machine, a piston slidably mounted within said air cylinder, an air chamber above said piston, said piston having a rod operatively connected to said stapling mechanism, said piston being resiliently mounted on said rod, valve means mounted in a vertical opening in said air cylinder and removed from alignment with said piston for directing compressed air above said piston and exhausting air from below said piston, said valve means having a valve means plunger extending outwardly below said air cylinder, lower stop means for said piston mounted in the bottom of said air cylinder and positioned to contact said piston inwardly of the outer edges, said lower stop means having a lower stop means plunger therein operatively connected to a valve trip lever for moving said valve means plunger and said valve means to a position allowing compressed air to enter beneath said piston and exhaust the air from above said piston, passages in said air cylinder connected to the exhaust sides of said piston during exhaust, said passages connected to a port above said stapling mechanism so that exhaust air is direeted through said stapling mechanism, said stapling mechanism having an adjusting means thereon for controlling the penetration of the retractable anvils therein.

3. An air operated stapling machine having a stapling mechanism therein, a magazine secured thereto for feeding staples thereto, an air cylinder secured to said stapling mechanism, said air cylinder having a handle with an air reservoir therein, a trigger pivotally mounted on said machine, a piston slidably mounted within said air cylinder having an upper head with a chamber above said piston, said chamber formed in part by cross passages in said upper head, the material between said passages acting as an upper stop for said piston and contacting said piston inwardly of the. peripheral edge thereof, said piston having a rod operatively connected to said stapling mechanism, said piston being resiliently mounted on said rod, valve means for directing compressed air above said piston and exhausting air from below said piston, said valve means mounted within a vertical opening in said air cylinder casing and removed from alignment with said piston and provided with means for adjusting same to prevent leakage, lower stop means for said piston mounted in the bottom of said air cylinder and positioned to contact said piston inwardly of the peripheral edge, said lower stop means having a plunger therein adapted to contact a valve trip lever for moving said valve means to a position allowing compressed air to enter beneath said piston and exhaust the air from above said piston, passages in said air cylinder connected to the exhaust sides of said piston during exhaust, said passages connected to a port above said stapling mechanism so that exhaust air is directed through said stapling mechanism, said stapling mechanism having an adjusting mechanism for controlling the penetration of the retractable anvil therein, said stapling mechanism having a staple driving blade with the lower rearward surface beveled, said magazine having a pusher with the upper forward surface beveled, said driving blade thereby pushing said pusher out of the way without harm and without the aid of a pusher stop means, and means for adjusting the piston rod within said air cylinder.

References Cited by the Examiner UNITED STATES PATENTS 2,899,935 8/59 Dalton 144.4 X 2,989,948 6/61 Forrester 1-44.4 2,995,113 8/61 Steiner 144.4 3,056,964 10/62 Beckman et al 1-44.4 3,086,207 4/63 Lingle et al. 1-444 GRANVILLE Y. CUSTER, 111., Primary Examiner.

ARTHUR M. HORTON, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,191,841 June 29, 1965 Werner Schafroth It is hereby certified that error appears in the above numbered patent reqiiring correction and that the said Letters Patent should read as correctedbelow.

Column 3, lines 62 and 63, for "itself. Thereby" read itself, thereby column 5 line 40, after "inder" insert said air cylinder Signed and sealed this 16th day of November 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Aucsting Officer Commissioner of Patents 

1. A POWER DRIVEN MACHINE HAVING A STAPLING MECHANISM THEREIN, AN AIR CYLINDER CONNECTED TO SAID STAPLING MECHANISM, SAID AIR CYLINDER BEING OPERATIVELY CONNECTED TO A SOURCE OF COMPRESSED AIR, A TRIGGER PIVOTALLY MOUNTED ON SAID MACHINE, A PISTON SLIDABLY MOUNTED WITHIN SAID AIR CYLINDER, SAID PISTON HAVING A ROD OPERATIVELY CONNECTED TO SAID STAPLING MECHANISM, AN AIR CHAMBER ABOVE SAID PISTON, SAID AIR CHAMBER HAVING DOWNWARDLY EXTENDING MEMBERS THEREIN ADATPED TO CONTACT AND FORM AN UPPER STOP FOR SAID PISTON SUBSTANTIALLY INWARDLY OF THE PERPHERAL EDGE THEREOF, SAID PISTON BEING RESILIENTLY MOUNTED ON SAID ROD, VALVE MEANS FOR DIRECTING 